Fe Alloys: Production and Metallurgical Aspects: Part I

JOM
Fe Alloys: Production and Metallurgical Aspects: Part I
DEAN GREGUREK 0
ZHIWEI PENG 0
CHRISTINE WENZL 0
JESSE F. WHITE 0
0 1.-Technology Center Leoben, RHI AG , Magnesitstrasse 2, 8700 Leoben , Austria. 2.-School of Minerals Processing and Bioengineering, Central South University , Changsha 410083, Hunan, China. 3.-RHI AG, Wienerbergstrasse 9, 1100 Vienna, Austria. 4.-Elkem Carbon AS, NO-4675, Kristiansand, Norway. 5.-
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Ferroalloys are closely linked to steel production:
only with the addition of ferroalloys can special
steels be produced with specific properties for even
the most challenging applications. Therefore, the
production quantities of ferroalloys are tightly
linked to steel production scale. The development
and manufacturing of high-tech steels require
highpurity additives that can be added in a controlled
and very precise manner. Hence, further
improvement of ferroalloy production processes is required
and a topic of ongoing research on industrial and
academic levels to meet the demands of the steel
producers and simultaneously allow for efficient and
economic ferroalloy production.
The present topic ‘‘Fe Alloys: Production and
Metallurgical Aspects’’ aims to provide JOM
readers with interesting reading material and updates.
The importance of the present topic also became
apparent in the volume of papers submitted. Due to
the large number of high-quality papers submitted,
the topic has been split into two parts, this being
part one, with the second part following in February
2017.
In ilmenite smelting, the aim is not the
production of a ferroalloy, even though metallic iron is
produced, but the main purpose is to remove the Fe
from the slag, which is mainly a mixture of Fe and
Ti oxides. Only after Fe removal can the remaining
Ti oxide slag fit the subsequent (white) pigment
production. The first article ‘‘Study of Porosity on
Titania Slag Obtained by Conventional Sintering
and Thermal Plasma Process’’ by Sneha Samal
investigates the development of porosity in ilmenite
during sintering via conventional and thermal
plasma heating. The physical dimensions and
Dean Gregurek, Zhiwei Peng, and Jesse White are the JOM advisors for
the Pyrometallurgy Committee of the TMS Extraction & Processing
Division, and guest editors for the topic Fe Alloys: Production and
Metallurgical Aspects: Part I in this issue.
morphology of the pores were characterized with
regards to the area fraction, mean diameter, shape
factor, and elongation factor. Under both
conventional and thermal plasma heating conditions,
porosity developed on the surface of ilmenite. The
two sintered ilmenite materials showed differences
in morphology and porosity. A lower porosity was
observed in the plasma-sintered sample when
compared with that obtained via conventional heating.
The standard rotary kiln–electric furnace (RKEF)
production route is a well-established and the most
common approach for ferronickel production despite
high energy consumption. Xiaodong Ma et al.
investigated a possible improvement in FeNi production
in their article ‘‘Efficient Utilization of Nickel
Laterite to Produce Master Alloy’’. They describe a
novel process for the smelting reduction of laterite
at a lower temperature by the addition of Mo/MoO3.
This results in a more effective metal–slag
separation and a reduction of the smelting temperature by
at least 100 K for the electric furnace process. The
addition of Mo/MoO3 decreased the melting point of
ferronickel alloys. Meanwhile, Mo served as a
collector to aggregate the ferronickel sponges for
better metal–slag separation.
Also the next article, ‘‘Phase Evolution and Ni-Fe
Granular Growth of Saprolitic Laterite Ore-CaO
Mixtures During Reductive Roasting’’ by Jun Luo
et al. deals with improvements in FeNi production,
namely the correlation between phase evolution,
fusion behavior and growth of Ni-Fe granules in
laterite ore/CaO mixtures during reductive
roasting. It was found that the fusion behaviors and the
granule growth are closely related to the contents of
CaO and FeO, as well as the CO partial pressure in
the gas mixture.
Slag properties are a vital factor for furnace
operation as they influence, for example, tapping,
metal/slag separation, operating temperature and
refractory corrosion. Therefore, Christoph Sagadin
et al. investigated the melting behavior of FeNi
slags in electric furnaces in the article ‘‘Melting
Behavior of Ferronickel Slags’’. Especially, the
enormously large slag amounts, their acidic
character and high melting temperatures pose
challenges for the ferronickel and refractory producers.
The main focus of this work was to achieve an
improved understanding of FeNi slags in the
electric furnace, namely both their melting behavior
and influence on refractory corrosion.
In all pyrometallurgical processes, especially
high-temperature ferroalloy production processes,
refractories are a decisive factor for smooth furnace
operation. Careful selection of proper refractory
qualities and functional lining design are
particularly important in new processes and furnace types.
The next article ‘‘Refractory Corrosion Mechanisms
in a Novel High Carbon Ferromanganese
Production Furnace’’ by Dean Gregurek et al. presents the
refractory design for a novel HCFeMn smelting
furnace that—other than standard submerged arc
furnaces—allows the processing of fine ores.
Postmortem investigations of selected refractory
samples such as basic and non-basic bricks,
castables and ramming materials installed in the
furnace provide valuable information about the
main wear mechanisms. Additionally, the process
slag and metal were investigated both practically
and theoretically by using thermodynamic
calculations, to better understand the corrosion
phenomena observed in the post-mortem samples.
The following papers being published under the
topic of Fe Alloys: Production and Metallurgical
Aspects: Part I provide excellent details and
research on the subject. To download any of the
papers, follow the url http://link.springer.com/jour
nal/11837/68/12/page/1 to the table of contents page
for the December 2016 issue (vol. 68, no. 12).
‘‘Study of Porosity on Sintered Ilmenite Using
Conventional Furnace and Thermal Plasma
Process’’ by Sneha Samal.
‘‘Efficient Utilization of Nickel Laterite to
Produce Master Alloy’’ by Xiaodong Ma, Zhixiang
Cui, and Baojun Zhao.
‘‘Phase Evolution and Ni-Fe Granular Growth of
CaO-mixed Saprolitic Laterite During Reductive
Roasting’’ by Jun Luo, Guanghui Li, Zhiwei Peng,
Mingjun Rao, Yuanbo Zhang, and Tao Jiang.
‘‘Melting Behaviour of Ferronickel Slags’’ by
Christoph Sagadin, Stefan Luidold, Christoph
Wagner, and Christine Wenzl.
‘‘Refractory Corrosion Mechanisms in a Novel
HighCarbon Ferromanganese Production Furnace’’ by
D. Gregurek, C. Wenzl, D. Kreuzer, A. Spanring, M.
Kirschen, D. Zeele, and J. Groenewald.